Stop motion for knitting machines



Dec.- 19 1939. M. WACHSMAN S IOP MOTION FOR KNITTING MACHINES Fiied Feb. 5, 1938 2 Sheets-Sheet 1 KNITTNG NEEDLE INVENTOR. M/C/Mfl WAfHSM/WV W 7 zfifiw? I Dec. E9, 1939; M. WACHSMAN 2,184,107

STOP MOTIbN FOR KNITTING MACHINES Filed Feb. 5, 1938 2 SheetS-Sheet 2 EIQET Q 7Q ATTORNEY Patented Dec. 19, 1939 UNITED STATES PATENT OFFiCE 2 Claims.

This invention relates to improvements in stop motions for knitting machines of the type in which a pivoted electric contact lever is under control of a travelling thread. When a knot or '5 other obstruction occurs in the thread, the lever is pulled down to cause an electric contact to be made whereby to actuate the stop mechanism of the knitting machine to stop the latter so that the thread can be attended to. The same operation takes place when a thread breaks or the thread runs out and another lever is moved up. The stop motion also includes so called guards which are members placed close to the levers for the purpose of overlying the thread which is placed upon the levers whereby .to prevent the yarn from jumping 01f the lever during the running of the machine. The guards also serve the purpose of preventing operation of the levers when a mere slack occurs in the thread.

One object of this invention is to provide a generally improved stop motion including novel features of construction whereby the mechanism may be easily adjusted with respect to the number of levers and guards employed. Another object is to provide a novel type of guard which' may be called dirtproof. Still another object is to include in a stop motion a number of levers for thread supporting purposes so arranged that when a slack occurs such levers move up and engage the thread to prevent the stop mechanism from operating to stop the machine.

Another object is to provide a double stop motion, that is a motion which consists of a single contact box upon which there is arranged a double set of thread controlling levers. The advantage of such a construction is better spacing of the threads, more room for placing the thread on the stop motion and it facilitates the discovery of broken threads.

With the foregoing and other objects in view the invention is embodied in a stop motion arranged and constructed as hereinafter set forth and as illustrated in the accompanying drawings in which Fig. 1 is a front view of the stop motion with parts broken away.

Fig. 2 is a view looking in the direction of arrow 2 in Fig. 1 with parts in section.

50 Fig. 3 is a plan view looking in the direction of arrow 3 in Fig. 2.

Fig. 4 is a detail view to show how the guards are supported.

Fig. 5 illustrates a modification with parts in section and parts broken away.

Fig. 6 is a View similar to Fig. 2 but shows a double stop motion.

Fig. '7 is a sectional View on line 1-1 of Fig. 6.

Fig. 8 is a sectional View on. line 8-8 of Fig. 6.

Fig. 9 is a diagrammatic View of a knitting 5 machine stop motion top showing the relation of the stop motion to the rotating shaft of the knitting machine.

Before describing the invention it should be recalled as well known in the art that a knitting machine is provided with an electrically actuated mechanism for stopping the machine when a thread breaks, runs out or a knot occurs. The electric circuit which controls the stop mechanism is normally open but is closed by the stop 15 motion when a lever or member therein is caused to close the circuit. Hence each stop motion includes a circuit terminal to be engaged by the lever or like member to close the circuit. The lever or member is itself the other circuit terminal as a part of the knitting machine upon which the circuit is grounded. All of this is common practise and well known in the art. Hence the drawings do not include any of such well known parts or mechanisms but is limited to illustrating only the stop motion itself. It is also well known that the threads or yarns in a knitting machine run from the bobbins to the knitting needles and that each thread is caused to pass through a stop motion before it reaches the needles, hence the stop motion is placed as far away from the bobbin and the needles as is conveniently practicable so that when the thread runs out or breaks there may remain sufiicient length of thread to be knitted into the fabric before the machine stops.

In the present invention the stop motion comprises a contact box H which may be of the general type and construction shown in my Patent No. 2,080,903, May 18, 1937. The box is usually made of sheet metal bent up to form the box proper which is covered by a removable front cover l2 to be secured in any suitable manner not especially illustrated. As shown, the cover may have a portion as l3 to which a bar 10 is attached. The box carries, properly insulated, a fixed circuit terminal It to which are secured contact springs I5 and I0.

Preferably the bar ID has a separate removable end bearing portion as shown at H. In the latter and in the box ll there is mounted a shaft I8 which passes through the box. Inside the box the shaft may carry a contact pin I9 adapted to engage the contact spring IE to close the circuit as will be hereinafter explained.

I The shaft l8 carries a number of pins or stems 20 and upon the latter are secured porcelain fingers 2! which extend forwardly of the box in spaced relation. The fingers 2! may be merely pushed onto the stems. or they may be otherwise removably or permanently secured. The fingers serve to support the'thread 44. The number of fingers to be used depends upon the nature of the thread. For certain kinds of thread a large number of porcelain fingers are desirable so that there may be a longer run of thread passing through the stop motion. The shaft [8 has a pin 22 which abuts a stop 23 on the box cover I 2, the shaft being held in a fixed position against said step by a spring 24 within the box.

The box supports another shaft 26 which has a contact heel 2! within the box for engaging the other contact spring 16. The shaft 26 is bent forward as at 45 to support a single porcelain finger 28 similar to the other fingers 2!. The

.finger 28 is under constant tension of a spring 38 connected to the contact heel 2i and which tends to move the finger 28 upwards.

The bar Ill supports a number of guards 32 in spaced relation between the fingers there being at least one guard between each two fingers. The guards are thin solid blades of sheet metal. l-leretofore such guards have been made of bent wire which necessarily includes many corners and bends in which dirt, paraffin and fuzz from the thread lodge easily and quickly to such an extent that frequent cleanings become necessary and at times such layers of dirt interfere with the operation of the stop motion. This is entirely eliminated with the present guards which present but little surface for the lodging of dirt.

The guards may be secured by any suitable means. As shown in Fig. 4 each guard has a rectangular hole 34 for sliding it on the bar ii). The guard has two punched out loops 35, 35 and a pin 36 passes through these loops and through a hole 3? in the bar. Thus the guards may be slid along the bar and spaced to suit. The front edge 38 of the guard is inclined so that the stop motion may be self-threading, By this is meant that in order to pass the thread through the stop motion the thread is merely dropped upon the inclined surfaces of the guards and the thread then slides downward until it falls upon all the porcelain fingers where it is snubbed under the guard noses M and comes to rest upon the porcelain fingers within enclosed spaces formed by the fingers, the guards, the guard noses and the guard back stops 4| which prevent the thread from sliding backwards and become entangled in the machinery. Each guard thus includes a body portion 32, an attaching portion $2, a guard nose 4%, and a back stop M. The guard may conveniently and economically be stamped from sheet metal in a single operation.

The operation of the device is as follows: The thread M passes upwards from a bobbin, not shown, over and upon all the porcelain fingers 2i and 28 and then down to the knitting needles, not shown. The fingers 2! are kept in normal circuit open positions by the pull of the spring 2s upon the shaft [8 and the shaft 26 is kept in circuit open position by the weight of the thread upon the finger 28 which balances the pull of the spring 30 as will be understood. When a knot occurs upon the thread so it can no longer run free, the thread will pull the porcelain fingers down, the shaft l8 will be rotated and the pin 19 will contact the spring IE to close the circuit. The machine Will stop, the thread will slide down off the fingers and the circuit will immediately be broken by the spring 24 moving the pin i9 away from the contact spring.

If the thread slack-S, the single finger 28 will then lift the thread and the finger might be moved into circuit closing position with the contact heel 2? engaging the other contact spring It were it not that the guards prevent the thread from being lifted off the other porcelain fingers. Thus the guards act as slack-stop preventing means and such function is known in the art.

If the thread breaks at the needles where breakage is apt to occur more often than in other places, the finger 28 will immediately be lifted by the spring 30 and the shaft 336 rotated so that the heel 2? may close the circuit at once and the mach ne be stopped. Hence it is important that the finger 23, which functions as an end detector, be placed on the needles side of the stop motion. Should the thread run out the same action will of course take place. the thread breaks between the stop motion and the bobbin, the finger 28 will also in this case lift the thread and the circuit will be closed.

As a matter of terminology in the art the fingers 52B are called knot detectors. They are normally held in circuit open positions by the spring 24 which keeps the pin 89 away from the contact spring is. When a knot occurs the pin 19 is pulled into contact with the contact spring l and the circuit is closed. The finger 28 is called an end detector because when the thread breaks or runs out this finger is lifted by its spring 30 so as to move the contact heel 2'! into engagement with the other contact spring it to close the circuit. The guards function as threading members, prevent escape of the thread from the fingers and act to prevent closing of the circuit when a mere slack occurs in the thread.

Fig. 5 illustrates a modification in which the knot detectors are of the type shown in my said Patent No. 2,080,903. The stems 2E! projecting from the shaft I3 carry porcelain detecmrs which include a body portion 59 having a backwardly bent tail 5|, a self-threading incline 52 and a thread supporting finger 66. When the thread is thrown against these detectors the tails 5i prevent the thread from falling down between the detector and the box H. In this instance the guards are in the form of single stems of wire 54 secured to the bar 55 which corresponds to the bar it. The guards overlie the thread as shown and function like the guards 32. The modification in Fig. 5 consists in the use of the porcelain knot detectors 50 with single wire guards 54 as shown. The other elements as shown in Fig. l are not changed or modified.

If desired the knot detector 59 in Fig. 5 may be substituted for the end detector 28 in Fig. 2 because it will also lift the thread if it is pulled upward by the spring 36. The latter is not shown in Fig. 2 because it would interfere with the showing of the spring 26. The construction inside the box is however quite well known in the art in stop motions of the instant type.

Referring now to Figs. 6 to 9 the stop motion there illustrated includes a box 55 upon which are supported the levers and guards described above and which bear similar reference numbers. The size of the box and the inside construction is different. The guards and levers are mounted on opposite sides of the box because this stop motion is to control two threads instead of one as in the preceding figures.

The two knot detector contact pins l9 on the two shafts I 8 are adapted to engage a double contact spring 66. The two contact heels 2'! on the two end detectors 28 are adapted to engage another double contact spring 67. The contact springs 66 and 6! are mounted side by side at different levels as shown in Figs. 6 and 8. They are connected to a single post 68 which is suspended from the top of the box and suitably insulated from the box. To the post is connected a. terminal connector 69. The four contact members controlling springs 24 within the box may conveniently be attached to nonturnable bearing plates 'lEI which are adjustable by screws H The plates move between the side walls of the box and a partition 12.

On the left side of Fig. 6 the drawing illustrates the parts in their position when a knot occurs in the thread and all the levers are pulled down. In this case contact pin l9 engages contact spring 65 as shown. On the right hand side the drawing shows the position of the levers when a thread breaks or runs out when the end detector 28 is pulled up and the contact heel 2'! engages the other contact spring 6 The box 65 may be made with two removable covers l2 as indicated in Fig. 6 where the one side of the box is broken away and sectioned.

The advantages of a double box will be apparent from Fig. 9. In the art it is well known to mount the stop motions on a so-called top and attach the top to the upright rotating shaft of the knitting machine. Such a top is indicated diagrammatically in Fig. 9 and consists of an upright shaft with arms 8|, see also Fig. 6, which carry the stop motions and an eye plate 82 through which the threads are guided from the bobbins and to the needles. There must be as many stop motions as there are threads in the machine. It follows that when the stop motions are placed in a circle at the top of the shaft 8|] there is little room to drop the thread on each stop motion. When the shaft is high confusion is apt to occur and if a thread causes stoppage it is at times difficult to discover quickly which thread needs attention. When double boxes are used as in Fig. 9 such confusion is eliminated. The operator can quickly discover a broken thread and there is more room for placing the thread on the levers. No attempt has been made to show details in Fig. 9 and the figure is to be taken only as illustrating the general arrangement.

Throughout the drawings many constructional details have been omitted and only the elements necessary for an understanding of the invention are shown.

I claim:

1. In a stop mechanism for knitting machines a circuit closer unit comprising a contact box, electric circuit terminal members in the box, a bar secured to the box, said bar having a depending bearing portion, a spring held knot detector shaft pivoted in the box and in said bearing portion between the same, said knot detector shaft including thread supporting fingers extending forwardly therefrom, said shaft having a contact member to engage one of the circuit terminals when said fingers are pulled down, a spring held end detector pivoted in the box and extending forwardly thereof between the knot detector fingers and the box and having a contact heel to engage one of the circuit terminals when the end detector is moved upwardly beyond a predetermined position, said end detector having a thread supporting finger positioned to be held alongside the knot detector fingers by a thread placed on the end detector finger, a spring continuously tending to move the end detector to bring its thread supporting finger above the knot detector fingers and move it to a circuit closing position and solid guard blades adjustably and removably supported on said bar and extending therefrom between the fingers aforesaid to hold the end detector against closing the circuit so long as a thread lies over the end detector finger, said guard blades forming with the said fingers thread enclosing spaces to prevent accidental escape of the thread.

2. In combination with an upright rotating shaft attached to a knitting machine, an eye plate on said shaft for guiding a plurality of threads from the bobbins to the needles of a knitting machine to which said shaft is attached, of a stop motion for said knitting machine including a circuit closer unit comprising an electric contact box secured to move with the shaft, electric circuit closing levers pivoted on said box and extending to both sides thereof and engaged by two of the said threads for controlling them in their passage to the needles of the knitting machine, electric circuit terminal springs within the box, contact members on said levers in normal circuit open position with relation to said terminal springs so long as the said two threads engage the said circuit closing levers, coiled springs for moving the said levers into engagement with the said terminal springs to close an electric circuit to stop the knitting machine when one of said threads breaks or a knot occurs therein, means for adjusting said coiled springs, a partition in said box for guiding said adjusting means and a fixed single circuit terminal extending downward from the top of the box for supporting the said circuit terminal springs.

MICHAEL WACHSMAN. 

